* writer each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned writer is closed.
   *
   * @throws IOException if an I/O error occurs while opening the writer
   */
  public abstract Writer openStream() throws IOException;

  /**
   * Opens a new buffered {@link Writer} for writing to this sink. The returned stream is not

   */

  @Override
  public void write(int c) throws IOException {
    checkNotClosed();
    target.append((char) c);
  }

  @Override
  public void write(String str) throws IOException {
    checkNotNull(str);
    checkNotClosed();
    target.append(str);
  }

  @Override
  public void write(String str, int off, int len) throws IOException {
    checkNotNull(str);
    checkNotClosed();

            return out;
          }
        });
    assertExpectedBytes(out.toByteArray());
  }

  public void testIsEmpty() throws IOException {
    assertEquals(expected.length == 0, source.isEmpty());
  }

  public void testSize() throws IOException {
    assertEquals(expected.length, source.size());
  }

  public void testSizeIfKnown() throws IOException {

        assertNotNull(testConverter);
    }

    @Test
    public void testInit() throws IOException {
        // Test init method (should do nothing)
        converter.init();
        // No exception should be thrown
    }

    @Test
    public void testConvertWithNoLanguages() throws IOException {
        // Test convert with no languages specified
        String text = "test text";

     */
    public abstract void connect() throws IOException;
    
    /**
     * Send data using RDMA
     */
    public abstract void send(ByteBuffer data, RdmaMemoryRegion region) throws IOException;
    
    /**
     * Receive data using RDMA  
     */
    public abstract ByteBuffer receive(int timeout) throws IOException;
    
    /**
     * Perform RDMA read operation
     */

  }

  public void testMarkNotSet() {
    IOException expected = assertThrows(IOException.class, () -> counter.reset());
    assertThat(expected).hasMessageThat().isEqualTo("Mark not set");
  }

  public void testMarkNotSupported() {
    counter = new CountingInputStream(new UnmarkableInputStream());

    IOException expected = assertThrows(IOException.class, () -> counter.reset());

  @Override
  public void write(byte[] b, int off, int len) throws IOException {
    throwIf(closed);
    throwIf(WRITE_THROWS);
    super.write(b, off, len);
  }

  @Override
  public void write(int b) throws IOException {
    throwIf(closed);
    throwIf(WRITE_THROWS);
    super.write(b);
  }

  @Override
  public void close() throws IOException {
    closed = true;
    super.close();
    throwIf(CLOSE_THROWS);

    asCharSink(to, charset, FileWriteMode.APPEND).write(from);
  }

  /**
   * Returns true if the given files exist, are not directories, and contain the same bytes.
   *
   * @throws IOException if an I/O error occurs
   */
  public static boolean equal(File file1, File file2) throws IOException {
    checkNotNull(file1);
    checkNotNull(file2);

  }

  public void testCopyTo_outputStream() throws IOException {
    ByteArrayOutputStream out = new ByteArrayOutputStream();

    assertEquals(bytes.length, source.copyTo(out));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());

    assertArrayEquals(bytes, out.toByteArray());
  }

  public void testCopyTo_byteSink() throws IOException {
    TestByteSink sink = new TestByteSink();

        failedChannel.setState(ChannelState.ESTABLISHED);

        when(mockChannelManager.getLoadBalancer()).thenReturn(mockLoadBalancer);
    }

    @Test
    void testHandleFailure() {
        IOException error = new IOException("Connection failed");

        failover.handleFailure(failedChannel, error);

        assertEquals(ChannelState.FAILED, failedChannel.getState());
        verify(mockChannelManager).removeChannel(failedChannel);